fix(auth): auto-detect OpenRouter credential from the pool, not just env (#42263)

resolve_provider() auto-detection only checked OPENROUTER_API_KEY/
OPENAI_API_KEY env vars, never the credential pool. A key added via
`hermes auth add openrouter` (manual pool entry, no env var) was invisible:
the provider failed to resolve or resolved with an empty api_key, so
requests went out with no Authorization header and OpenRouter returned
"HTTP 401: Missing Authentication header" while `hermes auth list` showed
the credential. Closes #42130.

- auth.py: check load_pool("openrouter").has_credentials() after the env check
- dump.py: `debug share` shows 'openrouter set (auth pool)' instead of the
  misleading 'not set' when the key lives in the pool
- add regression tests (pool credential auto-detects; empty pool still raises)

hermes_cli/auth.py

@@ -1561,6 +1561,21 @@ def resolve_provider(
     if has_usable_secret(os.getenv("OPENAI_API_KEY")) or has_usable_secret(os.getenv("OPENROUTER_API_KEY")):
         return "openrouter"
 
+    # Auto-detect an OpenRouter credential added via `hermes auth add openrouter`
+    # (manual pool entry, no env var). Without this, a key that only lives in
+    # the credential pool is invisible to auto-detection — the user sees
+    # `hermes auth list` showing the credential while requests go out with no
+    # Authorization header ("HTTP 401: Missing Authentication header"). The
+    # env-var check above only covers keys exported as OPENROUTER_API_KEY /
+    # OPENAI_API_KEY. See issue #42130.
+    try:
+        from agent.credential_pool import load_pool as _load_pool
+
+        if _load_pool("openrouter").has_credentials():
+            return "openrouter"
+    except Exception as e:
+        logger.debug("Could not check OpenRouter credential pool: %s", e)
+
     # Auto-detect API-key providers by checking their env vars
     for pid, pconfig in PROVIDER_REGISTRY.items():
         if pconfig.auth_type != "api_key":